Plain and simple: Google makes money if people use the internet. Anything that increases the number of times someone views a website makes google money.

It's like a billboard company offering to add free windows to your house so you watch their ads from your living room.

I agree with the motivation of your post. Monopolies are bad and customers have a vested interest in preventing google (or anyone else) from having monopolistic control of consumer internet. Unfortunately this is already true in many parts of the United States (Comcast is the only game in town where I live). At least in the short term Google entering this market should reduce monopolies not create them.